TESTING/MATGEN/dlaror.f(3)

NAME
TESTING/MATGEN/dlaror.f

SYNOPSIS

  Functions/Subroutines
subroutine dlaror (side, init, m, n, a, lda, iseed, x, info)
DLAROR

Function/Subroutine Documentation

  subroutine dlaror (character side, character init, integer m, integer n, double precision, dimension( lda, * ) a, integer lda, integer, dimension( 4 ) iseed, double precision, dimension( * ) x, integer info)

DLAROR

Purpose:

    !>
    !> DLAROR pre- or post-multiplies an M by N matrix A by a random
    !> orthogonal matrix U, overwriting A.  A may optionally be initialized
    !> to the identity matrix before multiplying by U.  U is generated using
    !> the method of G.W. Stewart (SIAM J. Numer. Anal. 17, 1980, 403-409).
    !>

Parameters
    SIDE

    !>          SIDE is CHARACTER*1
    !>          Specifies whether A is multiplied on the left or right by U.
    !>          = 'L':         Multiply A on the left (premultiply) by U
    !>          = 'R':         Multiply A on the right (postmultiply) by U'
    !>          = 'C' or 'T':  Multiply A on the left by U and the right
    !>                          by U' (Here, U' means U-transpose.)
    !>

    INIT

    !>          INIT is CHARACTER*1
    !>          Specifies whether or not A should be initialized to the
    !>          identity matrix.
    !>          = 'I':  Initialize A to (a section of) the identity matrix
    !>                   before applying U.
    !>          = 'N':  No initialization.  Apply U to the input matrix A.
    !>
    !>          INIT = 'I' may be used to generate square or rectangular
    !>          orthogonal matrices:
    !>
    !>          For M = N and SIDE = 'L' or 'R', the rows will be orthogonal
    !>          to each other, as will the columns.
    !>
    !>          If M < N, SIDE = 'R' produces a dense matrix whose rows are
    !>          orthogonal and whose columns are not, while SIDE = 'L'
    !>          produces a matrix whose rows are orthogonal, and whose first
    !>          M columns are orthogonal, and whose remaining columns are
    !>          zero.
    !>
    !>          If M > N, SIDE = 'L' produces a dense matrix whose columns
    !>          are orthogonal and whose rows are not, while SIDE = 'R'
    !>          produces a matrix whose columns are orthogonal, and whose
    !>          first M rows are orthogonal, and whose remaining rows are
    !>          zero.
    !>

    M

    !>          M is INTEGER
    !>          The number of rows of A.
    !>

    N

    !>          N is INTEGER
    !>          The number of columns of A.
    !>

    A

    !>          A is DOUBLE PRECISION array, dimension (LDA, N)
    !>          On entry, the array A.
    !>          On exit, overwritten by U A ( if SIDE = 'L' ),
    !>           or by A U ( if SIDE = 'R' ),
    !>           or by U A U' ( if SIDE = 'C' or 'T').
    !>

    LDA

    !>          LDA is INTEGER
    !>          The leading dimension of the array A.  LDA >= max(1,M).
    !>

    ISEED

    !>          ISEED is INTEGER array, dimension (4)
    !>          On entry ISEED specifies the seed of the random number
    !>          generator. The array elements should be between 0 and 4095;
    !>          if not they will be reduced mod 4096.  Also, ISEED(4) must
    !>          be odd.  The random number generator uses a linear
    !>          congruential sequence limited to small integers, and so
    !>          should produce machine independent random numbers. The
    !>          values of ISEED are changed on exit, and can be used in the
    !>          next call to DLAROR to continue the same random number
    !>          sequence.
    !>

    X

    !>          X is DOUBLE PRECISION array, dimension (3*MAX( M, N ))
    !>          Workspace of length
    !>              2*M + N if SIDE = 'L',
    !>              2*N + M if SIDE = 'R',
    !>              3*N     if SIDE = 'C' or 'T'.
    !>

    INFO

    !>          INFO is INTEGER
    !>          An error flag.  It is set to:
    !>          = 0:  normal return
    !>          < 0:  if INFO = -k, the k-th argument had an illegal value
    !>          = 1:  if the random numbers generated by DLARND are bad.
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 145 of file dlaror.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.